1. Field of the Invention
The present invention relates to an apparatus and a method for estimating a load of an engine having an actuator which can change a top dead center position of a piston.
2. Description of Related Art
Conventionally, a cylinder-internal pressure sensor is used for detecting a load of an engine. To use the cylinder-internal pressure sensor, however, since a space in which the cylinder-internal pressure sensor is disposed is required in a combustion chamber, a shape for the combustion chamber that is most suitable for combustion efficiency can not be employed. The cylinder-internal pressure sensor is also expensive.
The present invention has been accomplished in view of such a conventional problem, and it is an object of the invention to provide an engine load estimating apparatus and an engine load estimating method that estimates an engine load (output torque of the engine and a cylinder-internal pressure) without using a special-purpose sensor.